Biocatalysis and Strategies for Enzyme Improvement

Abstract

Biotransformation with the help of enzymes can greatly improve the rate and stereospecificity of reactions in organic chemistry. However, the use of organic solvents and harsh conditions in biotechnological applications often correlates with enzyme deactivation or a dramatic drop in catalytic activity. Detailed molecular understanding of the protein structure and conformational dynamics allows us to address such limitations and to finely tune catalytic activity by modifying the solvent, the support, or the active site of the enzyme. Along with physico-chemical methods of enzyme stabilization, such as additive approach, chemical modification, and immobilization of enzymes, approaches of enzyme engineering based on DNA recombination can be used to enhance the performance of biocatalysts. Since successful synthetic and industrial applications of biocatalysts require systems that are not only stable and active, but can also be reused in a continuous flow process reducing the production cost, the goal of this chapter is to introduce the reader to the vast scope of techniques available for enzyme improvement, highlighting their opportunities and limitations for the real-world technological processes.

Application of Carbon Nanotubes (CNTs) for Remediation of Emerging Pollutants - A Review

“…Bio-catalysis is part of biotechnology that converts organic compounds into other products with a minimum of waste through the utilization of enzymes the catalyst. The enzymes are fragile and prone to denature if the conditions such as pH and temperature are not suitable for their survival [38]. CNTs are used in bio-catalysis to immobilize enzymes and improve their catalytic stability, selectivity, and reusability [38,39].…”

Oxygen Generation Using Catalytic Nano/Micromotors

“…Several approaches can be used to generate gaseous oxygen, including photosynthesis [ 14 , 15 , 16 ], water splitting [ 17 ], oxygen concentrators [ 18 , 19 ], biological methods [ 20 , 21 ] and inorganic catalysis ( Figure 1 ) [ 22 , 23 , 24 , 25 , 26 ]. During photosynthesis, plants absorb sunlight, water and carbon dioxide molecules and convert them into biomass and oxygen [ 14 , 15 , 16 ] following the reaction: sunlight + n H 2 O + n CO 2 → (CH 2 O) n + n O 2 .…”

“…Similarly, oxygen concentrators are direct commercial oxygen production methods that can deliver a continuous ~90% pure oxygen stream in response to the rapid pressure-swing adsorption (RPSA) process characterized by short cycle time and high productivity ( Figure 1 b). Oxygen can also be obtained from various biocatalytic and enzymatic reactions by lowering the activation energy and decomposition of hydrogen peroxide (H 2 O 2 ) into water (H 2 O) and O 2 ( Figure 1 d) [ 19 , 20 , 21 ]. Recently, much attention has been given to oxygen generation based on single catalytic nano/microparticles, which can act as efficient heterogeneous micro-reactors integrated on the substrate or released in solution, i.e., for “on-the-fly” oxygen delivery.…”

Desenvolvimento, estudo e aplicações de nanobiocatalisadores proteolíticos magnéticos

“…As propriedades das enzimas também podem ser modificadas pela reação de grupos funcionais presentes nestas biomoléculas com outros compostos específicos, essa é a modificação química de enzima. Essas modificações podem trazer maior estabilidade, melhor eficiência catalítica, diferença em sua solubilidade, mudança em seu pH ideal entre outras (DÍAZ-RODRÍGUEZ;DAVIS, 2011;OSBON;KUMAR, 2020).…”

“…O aprisionamento (Figura 8B) consiste em prender a enzima na malha de um polímero, e como no caso da adsorção, é um processo simples, não altera profundamente a estrutura do catalisador e não requer uma grande quantidade dele; seus pontos negativos são a possível perda de catalisador para o meio e a sua restrição ao substrato, que tem que ser pequeno o suficiente para entrar na malha. O encapsulamento (Figura 8C) é parecido com o aprisionamento, mas, ao invés de ficar presa na malha de um polímero, a enzima fica confinada por uma membrana que permite que haja um microambiente separado para ela; a sua principal vantagem é a alta eficiência catalítica; já a desvantagem é que pode ocorrer inativação da enzima e a membrana pode interferir no transporte de massa caso o substrato seja muito volumoso ou de alta massa molar (DWEVEDI, 2016;OSBON;KUMAR, 2020). Os métodos de imobilização por ligação química são os de ligação covalente, "cross-linking" e ligação iônica que, em geral, são irreversíveis.…”